DE19953072A1 - Geothermal heat utilization apparatus has throttle for making working medium vaporizable - Google Patents

Abstract

The apparatus includes a first channel (10) for carrying a working medium (12) such as ammonia down into the earth, and a second cannel (14) for returning it to the surface. The two channels form a system that is closed to the earth. The medium is supplied downwards into the earth via a throttle region (15,16) which throttles the substantially liquid medium so that it assumes an evaporation pressure in front of the throttle region. The medium behind the throttle region is completely vaporizable.

Description

State of the art

The invention is based on a device according to the Oberbe handle of claim 1.

A heat flow flowing from the interior of the earth is approx. 80% on the decay of radioactive isotopes in rocks and at approx. 20% attributable to the heat of origin in the formation of the earth ren. The temperature from the earth's surface to the interior of the earth increases by approx. 30 ° C per 1000 m. In the area of geothermal Abnormalities can occur with larger temperature increases for example due to its geographical proximity to Mag macaques in the earth's crust (intrusions), currents from Tie lake waters etc. Such areas are used in particular for Use of geothermal energy preferred.

The geothermal energy can be stored in different substances, in principle in water vapor, in water and / or in are called layers of rock.  

Stored water vapor is usually in the vicinity of active volcanoes and very rugged or water-bearing Bedrock. The steam can be directed to the surface of the earth and - after an often necessary separation of entrained Water - used to generate electricity. Usable steam However, sources are only available in a few areas.

The energy stored in layers of earth in hot water is usually preceded by a duplicate direction opened up. The duplicate has a conveyor boho tion through which the hot water from the appropriate earth layers to the surface of the earth can be promoted. In order to avoid the hydrostatic pressure in the layers of earth decreases over time, the influx of hot water returns and especially to make better use of the warmth of the rock to be able to cool the cooled via an injection hole Water returned to the corresponding layers of the earth. The Water can flow through the rock from the injection hole Production bore flow and is heated in the process. That from the Water that is extracted from the earth generally becomes a space heater used.

To unlock the stored in hot rock strata ten energy is a so-called hot-dry-rock process knows. In this procedure, a first procedure a first deep hole of approx. 5000 m was drilled. about the deep well becomes water with high pressure in approx. 5000 m Pressed deep into the rock so that there are cracks in the rock form. With a second deep hole is at a distance from about 500 m the area where the cracks are drilled have trained. Then water can flow over a depth  hole pumped into the rock, through the cracks to the second Deep hole and through the second deep hole warms to the earth's surface. To costly To avoid incorrect drilling, the cracks in the rock should be ge be located. This is special at a depth of 5000 m difficult and expensive.

Furthermore, a generic device with three concents trisch arranged pipes known, with a so-called called outer downspout, a cladding tube and an inner Riser pipe. Cold water flows down through the downpipe pumped into the interior of the earth, warmed and through the riser warms up promoted. An annular gap with air between the riser and the cladding serve as insulation between the outer downpipe and the inner riser. The pipes are impermeable to the earth from a waterproof Surround suspension, for example, of concrete. A fabric exchange with the ground is avoided. The efficiency for However, generation of electrical energy is low.

The invention has for its object the generic Develop device and especially the effect degree to generate electrical energy and the Reduce costs. It is according to the invention by the Features of claim 1 solved. Further refinements he give themselves from the subclaims.  

Advantages of the invention

The invention relates to a device for using Geothermal energy with at least one first channel through which an ar Beitsstoff down into the earth and with at least one second channel through which the working substance goes up, in Rich tion earth surface, the first and the second channel form a system closed to the ground.

It is suggested that the working substance at least a throttle area is directed down into the interior of the earth and the throttle area in the flow direction in front of the Dros selbereich largely liquid working fluid on a Ver steam pressure throttles, so that the working fluid after Throttle area is largely completely evaporable. The Working fluid can advantageously be down in the liquid state and in the gaseous state, with low density upwards leads. The fluid pressure building up or gravity acting on the liquid can be pressure increase in a clockwise cycle be used, which means a particularly high efficiency, especially in the generation of electrical energy is cash. Basically, however, can be used to generate a pressure upstream of the throttle area also a pump be used that supports the liquid column or generates the required pressure alone.

If the working substance is largely after the throttle area, advantageously completely evaporated, it flows upwards to the earth's surface. During operation of the device  the introduction of an external service, in particular a pump performance, avoided and thus increased efficiency become. In the second channel in the gas column of un a slight pressure drop upwards. On the ground the surface of the vaporous working material is far higher pressure than in an initial state of the process, the be particularly advantageous for generating electrical energy can be used. The throttle range can be one or advantageously be formed by several throttling points, which in Flow direction with a distance from each other are arranged. With several throttling points one can be special high pressure in the upper area of the second channel reached become.

In a further embodiment of the invention is pre beat that in the direction of flow after the second channel Compressor is arranged over which the working fluid before Throttle range is compressible. The throttle range can be particularly advantageous in the upper region of the first channel can be arranged and it can be advantageous over the entire first th channel a large temperature difference between the Ar beitsstoff and the interior of the earth and therefore a good warmth transition from inside the earth to the working material. The energy supplied from the interior of the earth can be advantageous largely constant evaporation temperature of the working fluid fes can be used for evaporation. Owns in the second channel the working substance largely the same temperature as in the first th channel, creating isolation between the channels can be saved. To obtain a large amount of heat a small drilling depth can be sufficient.  

The throttle range can basically be one or more ren, throttling points which appear to be suitable to the person skilled in the art be educated. However, at least it is particularly advantageous a throttle point formed by at least one tube. It can with a sufficient throttling effect a relatively ge rings flow velocity through the throttle point and thus low wear and a long service life be enough.

In one embodiment of the invention it is proposed that the first and the second channel to a closed system connected, d. H. not just below the surface of the earth, son connected above the surface of the earth are. An escape of the working fluid from the system can ver avoid and it can be advantageous to use a working material be a special with the lowest possible costs high efficiency is achievable.

If the working fluid has a lower boiling temperature than Water can be compared to water powered devices the working material already at shallow depths or shallow ren temperatures to be evaporated, thereby ins special drilling costs can be saved. As working are commonly used refrigerants such as especially ammonia.

To reduce the flow velocity in the first channel and increase the surface area and thereby the heat transfer Improving gear on the working material is advantageous in first channel at least one after the throttle area introduced the working element deflecting element. In the first  filling channel can advantageously be introduced, that redirect the working material. In another configuration tion is proposed that instead of packing at least egg ne spiral path is inserted, over which the working material to the outer wall of the first channel is directed, which leads to advantageous film evaporation the outer wall of the first channel can be reached. The Web can be made of different materials, for example, the path can be formed by a sheet metal part or can also be formed in one piece with a channel wall his. The web preferably has no sealing functions on in the channel.

In one embodiment of the invention, the first and the second channel in a material-tight lined deep hole arranged and the working material is in the radially outer Be rich within the deep hole downwards and in the radial inner area of the deep hole through an inner tube headed above. Additional deep holes and thus connected their costs can be saved. Furthermore, the Kanä le particularly simple and inexpensive under the surface of the earth che be connected together. Basically However, the working material can also be tied over one or more tie bores down and over one or more, of which ge separate deep holes are directed upwards.

drawing

Further advantages result from the following drawing spelling. In the drawing, an embodiment of the  Invention shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently use the features individually consider and put together into meaningful further combinations grasp.

Show it:

Fig. 1 is a schematic representation of an inventive device and

Fig. 2 procedures in a pressure enthalpy diagram and

Fig. 3 shows a variant of Fig. 1,.

Description of the embodiment

Fig. 1 shows an inventive device for the use of geothermal energy with a first channel 10 through which a Ar beitsstoff 12 down into the interior of the earth and with a second channel 14 through which the working material 12 is directed upwards in the direction of the earth's surface. The first channel 10 is formed by a first outer tube 52 , which is inserted into a deep hole 36 and the deep hole 36 is lined with fabric to the outside. The outer tube 52 is sealed at the lower end, on its end face. The second channel 14 is formed by an inner tube 46 arranged concentrically to the outer tube 52 in the radially inner region of the deep bore 36 . The inner tube 46 is surrounded by a cladding tube 56 which encloses an annular gap 58 with air to the inner tube 46 for insulation and delimits the first channel 10 radially inward. The first and the second channel 10 , 14 are connected together with a system 60 to form a closed system so that the ammonia used as the working substance 12 cannot escape to the outside.

According to the invention, the first channel 10 has a throttling area 16 with three throttling points 22 , 24 , 26 connected in series in the flow direction. The throttle points 22 , 24 , 26 are each arranged at a distance from one another and are each formed by a tube 28 , 30 , 32 fastened in a flange 40 .

When building the device, the outer tube 52 , the cladding tube 56 and the inner tube 46 are already introduced concentrically with the drilling of the deep drilling 36 in sections. The sections are sealed together at the axial joints by welding. In principle, however, the sections can also be connected in a cohesive, form-fitting and / or non-positive manner by means of various methods which appear to be useful to the person skilled in the art.

The flange 40 can be fastened between the outer tube 52 and the cladding tube 56 using various methods which appear suitable to the person skilled in the art. However, this is particularly advantageously welded to the outer tube 52 and the cladding tube 56 before the tubes 46 , 52 , 56 are inserted into the deep bore 36 . In order to avoid that the first channel 10 becomes soiled during drilling or to prevent drilling mud and / or a suspension from running into the first channel 10 , the first channel 10 is already in the lowest section before it is inserted into the deep bore 36 axial end face closed with a steel plate 54 . A drill head of a drilling device, not shown, can be guided up and down through the inner tube 46 in the folded state. The second channel 14 can be cleaned after completion of the drilling process. After completion of the deep bore 36 , the inner tube 46 is sealed on its axial end face pointing downward with a plastic plate 42 to the ground. In addition, the axial end face of the inner tube 46 can be tightly sealed with all methods which appear suitable to the person skilled in the art, for example by pouring out and / or by pressing in a Teflon body, as a result of which a non-positive and positive closure could be created, etc. Fer ner possible to insert the cladding tube 56 and / or the inner tube 46 only subsequently into an outer tube which is tightly closed on its downward-facing end face.

Before the inner tube 46 and the cladding tube 56 are introduced , openings 136 , 138 or bores are made in their lowermost sections. The openings 138 in the inner tube 46 who then closed forcefully and positively or in a suitable manner before insertion, so that on the one hand they reliably prevent contamination of the cavities between the tubes 46 , 52 , 56 and on the other hand due to the filling with ammonia resulting pressure difference between the first channel 10 and the second channel 14 are free again. The openings 136 , 138 or only the openings 138 can, however, also be introduced subsequently, after the introduction of the tubes 46 , 52 , 56 or can be closed with substances that chemically dissolve in ammonia, but against those used in the production of the bore Substances are resistant.

At the start of commissioning, all valves 72 , 74 , 76 and 84 to 128 , 140 are open. In order to fill the first channel 10 as quickly as possible with liquid ammonia, liquid ammonia is passed at about 25 bar via a line 64 and via the second channel 14 into the device. If only one throttle point is arranged in the first channel 10 , the device can also be filled via the first channel 10 . The device is vented via lines 68 , 70 , which open into a water bath, not shown. If there are no more air bubbles in the water bath, the valves 72 , 74 in the lines 68 , 70 can be closed. If a certain fill level is detected with a fill level meter 78 in a condensate store 66 , the valve 76 in the line 64 is closed. Valves 94 , 96 and 98 are also closed.

The pressure p in the second channel 14 is then reduced via a jet pump 50 , which is supplied with ammonia from the condensate storage 66 by a propulsion jet pump 80 , and the ammonia in the second channel 14 is thereby evaporated. The ammonia pumped by the jet pump 50 is condensed in a heat exchanger 130 and returned to the condensate storage 66 .

If a temperature is detected at a measuring point 82 , which indicates that the ammonia in the second channel 14 is completely or at least largely evaporated, the propulsion jet pump 80 is switched off and the valves 84 , 86 are closed. In order to dissipate heat exclusively via a heat exchanger 132 to a consumer (not shown in detail), only the valve 94 is then opened. In order to generate electrical energy with a turbine 134 and a generator 62 , the valves 96 and 98 are opened.

During the operation of the device, liquid ammonia is conducted from the condensate store 66 via the valves 126 and 92 into the first channel 10 . The ammonia is liquid in a first region 48 of the first channel 10 . From the starting point P1 in the upper area of the liquid column in the first channel 10 , the pressure p increases downwards due to gravity, namely the pressure p at point P1 is approx. 25 bar and at point P2 at a depth of 1650 m approx. 100 bar ( Fig. 2). The pressure p is throttled by the throttling point 22 at a depth of 1650 m. After the throttle point 22 be the pressure p in P3 is about 45 bar. The pressure p increases from P3 to P4 due to the gravity of the liquid column and is approximately 105 bar in P4 at a depth of 2850 m. From P4 to PS, the pressure p is throttled by the second throttling point 24 at a depth of 2850 m. The pressure p increases from PS to P6 to approx. 105 bar at a depth of 3850 m. From P6 to P7, the pressure p is throttled by the third throttling point 26 at a depth of 3850 m to an evaporation pressure 18 of approximately 60 bar. Between the throttling points 22 , 24 , 26 , the ammonia is always supplied with heat from the ground, where the enthalpy h increases between the throttling points 22 , 24 , 26 .

From P7 to P8 the enthalpy h increases at constant pressure p due to the pressure energy, from P8 to P9 due to the cooling of the superheated ammonia and from P9 to P10 due to the heat input from the ground. In order to achieve a good heat transfer from the ground to the ammonia, 26 filling bodies 34 are introduced in the first channel 10 after the lowest throttle point ( FIG. 1). The ammonia is completely evaporated at point P10 at a depth of approx. 4600 m and can flow from the first channel 10 via the openings 136 , 138 in the cladding tube 56 and in the inner tube 46 into the second channel 14 ( FIG. 1). In order to avoid that the ammonia gas rises in the annular gap 58 , between the cladding tube 56 and the inner tube 46 , the annular gap 58 is closed with a closure part 38 above the openings 136 , 138 towards the surface of the earth. The closure member 38 is fixed according to the flange 40 of the throttling points 22 , 24 , 26 tion 36 before insertion into the Tiefenboh. The ammonia gas flows in the second channel 14 upwards to the earth's surface. The pressure p and the enthalpy h decrease from P10 to P11. At point P11 the ammonia gas has approx. 40 bar, ie approx. 15 bar more than in starting point P1. The excess energy from P11 to P1 can be used for heat dissipation to consumers - P11-P12-P13-P1 - or can be used for generating electrical energy and for heat dissipation - P11-P12a-P1 -. A closed, right-handed circular process is created. Instead of having several throttle positions 22 , 24 , 26 , the device can also be operated with only one throttle position. In Fig. 2, a process flow of a device with only one throttle point is shown with a dashed line. The ammonia is throttled in comparison to several throttling points to a low evaporation pressure 20 .

For power control, the inflow from the condensate reservoir 66 into the first channel 10 can be regulated via the valve 126 . The liquid column should not sink below the first throttle point 22 . To turn off the device, either the supply from the condensate storage 66 to the first channel 10 can be interrupted and / or the liquid ammonia can be pumped out of the condensate storage 66 via a pump 44 into the inner tube 46 , whereby the device can be switched off particularly quickly can. In addition, the pump 44 can be used for restarting.

FIG. 3 shows a variant of the device shown in FIG. 1. Components that remain essentially the same are fundamentally numbered with the same reference numerals. The device has a first channel 10 through which the Ar beitsstoff 12 down into the earth's interior and a second channel 14 through which the working substance 12 is directed upwards towards the surface of the earth. The first channel 10 is formed by an outer tube 52 which is inserted into a deep bore 36 and which lines the deep bore 36 in a material-tight manner to the outside. The outer tube 52 is sealed at the lower end, on its end face. The first channel 10 is delimited radially inward by an inner tube 152 which is arranged concentrically with the outer tube 52 and forms the second channel 14 . In the first channel 10 , between the tubes 52 and 152 , a downwardly spirally extending web 35 is introduced, which directs the working material 12 to the outer wall of the first channel 10 or to the inner surface of the outer tube 52 . The web 35 also serves as a spacer between the tubes 52 and 152 . The web 35 can extend over the entire length of the channel 10 or can advantageously be arranged in individual length sections, between which there was a stand. The web 35 does not perform a sealing function in the first channel 10 . The first and the second channel 10 , 14 are connected together with a system 154 to form a closed system, so that the ammonia used as the working substance 12 cannot escape to the outside.

The upward flowing in the second channel 14 , vaporous Am moniak is compressed in a compressor 142 downstream of the second channel 14 , to about 25 bar and heated to about 130 ° C or overheated. In a heat exchanger 144 connected downstream of the compressor 142 , heating water is heated in three phases, namely in a first phase by cooling the ammonia down to a condensation temperature, in a second main phase by condensing the ammonia and in a third phase by cooling the condensate. The heating water is further heated in a heat exchanger 144 downstream exhaust gas heat exchanger 150 by exhaust gases 146 of a motor 148 of the compressor 142 .

The working fluid 12 has about 45 ° C after the heat exchanger and is passed after the heat exchanger 144 via a throttle region 15 arranged in the upper region of the first channel 10 or via a throttle point and thereby from approx. 25 bar to an evaporation pressure of approx. Throttled 4 bar. The throttle area 15 or a throttle point can also be arranged in a line in front of the first channel 10 .

The working substance 12 cools down to about 0 ° C. by throttling. The liquid working fluid 12 is guided downwards by the web 35 and by centrifugal force to the outer wall of the first channel 10 , on which film evaporation occurs. The vaporized working fluid 12 is passed through an ensuing total flow in the first channel 10 down and in the second channel 14 upwards. In the first and in the second channel 10 , 14 , the working substance 12 essentially has its evaporation temperature of approximately 0 ° C. It can achieve a particularly good heat transfer from Erdin neren to the working material 12 and also insulation between the first channel 10 and the second channel 14 can be saved.

reference numeral

10th

channel

12th

Working material

14

channel

15

Throttle range

16

Throttle range

18th

Evaporation pressure

20th

Evaporation pressure

22

Throttling point

24th

Throttling point

26

Throttling point

28

pipe

30th

pipe

32

pipe

34

Packing

35

train

36

Deep drilling

38

Closure part

40

flange

42

Plastic plate

44

pump

46

Inner tube

48

Area

50

pump

52

Outer tube

54

steel plate

56

Cladding tube

58

Annular gap

60

investment

62

generator

64

management

66

Condensate storage

68

management

70

management

72

Valve

74

Valve

76

Valve

78

Level meter

80

Jet pump

82

Measuring point

84

Valve

86

Valve

88

Valve

90

Valve

92

Valve

94

Valve

96

Valve

98

Valve

100

Valve

102

Valve

104

Valve

106

Valve

108

Valve

110

Valve

112

Valve

120

Valve

122

Valve

124

Valve

126

Valve

128

Valve

130

Heat exchanger

132

Heat exchanger

134

turbine

136

opening

138

opening

140

Valve

142

compressor

144

Heat exchanger

146

Exhaust gas

148

engine

150

Exhaust gas heat exchanger

152

Inner tube

154

Investments
P1 state point
P2 state point
P3 state point
P4 state point
P5 state point
P6 state point
P7 state point
P8 state point
P9 state point
P10 state point
P11 state point
P12 state point
P12a state point
P13 state point
p pressure
h enthalpy

Claims (20)

1. Device for using geothermal energy with at least a first channel ( 10 ) through which a working substance ( 12 ) down into the interior of the earth and with at least a second channel ( 14 ) through which the working material ( 12 ) upwards, towards the earth surface is passed, the first and the second channel ( 10 , 14 ) forming a closed system to the ground, characterized in that the working substance ( 12 ) is guided downward through at least one throttle region ( 15 , 16 ) and the Dros selbereich ( 15 , 16 ) throttles in the direction of flow before the throttle area ( 15 , 16 ) largely liquid working fluid ( 12 ) to an evaporation pressure ( 18 , 20 ), so that the Ar beitsstoff ( 12 ) after the throttle region ( 15 , 16th ) is largely completely evaporable. 2. Apparatus according to claim 1, characterized in that to increase the pressure upstream of the throttle region ( 16 ) the accumulated liquid column of the working substance ( 12 ) acting on egg ne before the throttle region ( 16 ) is used by gravity. 3. Device according to claim 1 or 2, characterized, that a pump to increase the pressure before the throttle area is arranged. 4. Apparatus according to claim 2 or 3, characterized in that the throttle region ( 16 ) of a first and at least at least a second throttle point ( 22 , 24 , 26 ) is formed, which in the direction of flow to the first throttle point ( 22 ) at a distance is arranged. 5. Device according to one of the preceding claims, characterized in that in the flow direction after the second channel ( 14 ) a United poet ( 142 ) is arranged, via which the working fluid ( 12 ) in front of the throttle region ( 15 ) is compressible. 6. The device according to claim 5, characterized in that the compressor ( 142 ) is arranged in the flow direction in front of at least one heat exchanger ( 144 ). 7. The device according to claim 6, characterized in that exhaust gases ( 146 ) of the compressor ( 142 ) driving Mo tors ( 148 ) are passed through an exhaust gas heat exchanger ( 150 ). 8. Device according to one of claims 5 to 7, characterized in that the throttle region ( 15 ) is arranged in the upper region of the downwardly leading, first channel ( 10 ). 9. Device according to one of the preceding claims, characterized in that the throttle region ( 16 ) has at least one throttle point ( 22 , 24 , 26 ) which is formed by at least one tube ( 28 , 30 , 32 ). 10. Device according to one of the preceding claims, characterized in that the first and the second channel ( 10 , 14 ) are connected to form a closed system. 11. Device according to one of the preceding claims, characterized in that the working substance ( 12 ) has a lower boiling temperature than water at the same pressure. 12. The apparatus according to claim 11, characterized in that the working substance ( 12 ) is ammonia. 13. Device according to one of the preceding claims, characterized in that at least after the throttle region ( 16 ) in the first channel ( 10 ) at least one element ( 34 , 35 ) deflecting the working substance ( 12 ) is introduced. 14. The apparatus according to claim 13, characterized in that in the first channel ( 10 ) the working material ( 14 ) deflecting filler ( 34 ) are introduced. 15. The apparatus according to claim 13, characterized in that in the first channel ( 10 ) at least one spiral downward path ( 35 ) is introduced, via which the Ar beitsstoff ( 12 ) on the outer wall of the first channel ( 10 ) is tet is. 16. The device according to one of the preceding claims, characterized in that the first and the second channel ( 10 , 14 ) are arranged in a tightly lined deep hole ( 36 ) and the working material ( 12 ) in the radially outer region within the deep hole ( 36 ) downwards and in the radially inner region of the deep bore ( 36 ) through an inner tube ( 46 , 152 ) upwards. 17. A method of operating a device according to one of the preceding claims, characterized in that in a first region ( 48 ) of the first channel ( 10 ) largely liquid working substance ( 12 ) in a second region ( 15 , 16 ) to an evaporation pressure ( 18 , 20 ) throttled, then largely completely evaporated and in the vapor state in the second channel ( 14 ) is sent upwards. 18. The method according to claim 17, characterized in that the working substance ( 12 ) is throttled in at least two steps to the evaporation pressure ( 18 ) in the second region ( 16 ) by a first and at least a second throttle point ( 22 , 24 , 26 ) , Heat being supplied to the working substance ( 12 ) between the throttle points ( 22 , 24 , 26 ). 19. The method according to claim 17 or 18, characterized in that when the device is started up, the working substance ( 12 ) is supplied via the second channel ( 14 ). 20. The method according to claim 19, characterized in that during commissioning after filling the device with a pump ( 50 ) the pressure (p) in the second channel ( 14 ) is reduced and the working fluid ( 12 ) in the second channel ( 14 ) ver is steaming.